IMAGE-ANALYSIS OF EFFECTS OF 4 DRUGS ON C ORONARY-OCCLUSION AND MYOCARDIAL REPERFUSION INJURY

Myocardial infarction induced by coronary occlusion (O model) and repe rfusion (R model) and the effects of nitroglycerin (Nit), propranolol (Pro), lidocaine (Lid), nifedipine (Nif), and saline were studied in r ats by image analysis and weighing methods. The results showed that th e myocardial infarct size (MIS) in R and O models were 27+/-8% and 39/-6%, respectively (P < 0.01). The roundness and the distances from th e border of the infarct zone (IZ) to endocardium or epicardium in R mo del were greater than those in O model, while the gray level differenc e between normal and infarct myocardium (DELTAG) in the R model was le ss than that in 0 model. MIS of Nit group in O and R models were 23+/- 12% and 16+/-7%, respectively, which were significantly less than thos e in Lid, Nif groups, and saline. The reduction of MIS was also found in Pro group in both models. The results suggested that early restorat ion of blood flow resulted in the salvage of injured myocardium and Ni t and Pro were found to have beneficial effects in both models.